Cytoskeletal changes of glioblasts after morphological differentiation induced by glia maturation factor.

There were specific changes in the contents of cytoskeletal components and their organization during glioblast differentiation induced by glia maturation factor (GMF). Vimentin and glial fibrillary acidic protein increased in their contents, whereas actin did not. Tubulin was only a minor component of the glial cytoskeleton. Diffusely distributed intermediate filaments decreased and a number of fiber bundles were formed in parallel with the long axis of the large processes. The microtubules forming radiating fibers from the nuclear matrix to the cell body periphery were rearranged in such a way that the fibers perpendicular to the nuclear axis decreased whereas those parallel to the axis remained unchanged. Lattice type microfilaments decreased and stress fibers disappeared. The perimeter of the glioblasts, especially terminal webs, was hemmed presumably by actin and made contact with the substratum.